The present invention pertains to flat cable and a method of making flat cable and, in particular, flat electrical cable with exposed conductors without adhesive residue.
Flat electrical cables are well known in the art having conductors sandwiched between two insulating layers. Flat conductor cable is known in the art having an upper insulator layer having an adhesive adhered to a first side of the upper layer and a lower layer of insulating material having an adhesive adhered to a first side of the lower layer. A conductor or strands of conductors are placed between the upper and lower insulator layers and all three layers are secured together by the adhesive. However, use of adhesive to bond the layers is disadvantageous in that upon heating of the adhesive, the conductors may float in the free flowing adhesive causing the spacing between the conductors to be inconsistent and non-parallel. Upon drying and attempted attachment of the flat cable to a component, the improperly placed conductor may not align with the conductive leads of the component. The cable is to be attached to and the flat cable is unusable and must be discarded. Further, when the cable is stripped to expose the conductors for connection of the cable to a component, the conductors have an adhesive residue thereon which inhibits the conductive properties of the conductor. Also, if any scrap material of the insulator layers is produced, the scrap may not be recycled due to the presence of the adhesive on the insulator layer.
Other bonding techniques are known in the art for bonding multiple layers such as ultrasonic welding. Generally ultrasonic welding has been used for spot welding with thermoplastic materials using a plunge mode. Ultrasonic welding using a continuous weld or a shear mode has only been known for welding metals. Therefore, the known methods of welding thermoplastic materials using ultrasonics did not provide for a continuous welded seam and the seam, therefore, does not have great pull strength. In the area of electrical cables, seams of great pull strength are required and the previously known welding techniques are not sufficient. Therefore, it is an object of the present invention to provide a flat electrical cable which is bonded without use of adhesives and provides for a continuous seam.
It is another object of the invention to provide a method of assembling a flat cable by bonding without using adhesives and to provide a continuous seam.
It is a further object of the present invention to provide a flat cable having exposed conductors without an adhesive residue.
It is another object of the present invention to provide a flat cable which has a pattern on one side of the cable in order to reduce friction of that one side against other surfaces.
It is a further object of the present invention to provide a method of assembling a flat cable which allows for the recycling of waste materials and provides for a quick and inexpensive method of manufacturing the flat cable.
It is a further object of the present invention to provide a method of manufacturing flat cable which may be tested by a vision system in order to ensure that a proper bond has been formed between the insulator layers.
It is another object of the present invention to provide a flat cable which allows for the exposure of the conductors without the use of grinding equipment.